Add automated test for "Create Template Provider from the Class UI"

The manual test is here: https://test.xwiki.org/xwiki/bin/view/Other%20Tests/Create%20Template%20Provider%20from%20the%20Class%20UI

The test verifies that a Template Provider can be created from a Class UI.

Matrix discussion:

Vincent Massol: found the question: https://matrix.to/#/!ikPtGZaGWtyblizzlR:matrix.xwiki.com/$16142520628626wlVBi:matrix.xwiki.com?via=matrix.org&via=matrix.xwiki.com&via=matrix.wina.be
Ilie Andriuta: thanks Vincent Massol
Vincent Massol: we have a test for the xclass app: https://github.com/xwiki/xwiki-platform/blob/a6bd6aa1e3c3aa96d480812fa9f635ca369384b8/xwiki-platform-core/xwiki-platform-xclass/xwiki-platform-xclass-test/xwiki-platform-xclass-test-docker/src/test/it/org/xwiki/xclass/test/ui/ClassSheetIT.java#L45
and it has a part about template creation

// Create the template.
 classSheetPage = classSheetPage.clickCreateTemplateButton().waitUntilPageIsLoaded()
 .clickAddObjectToTemplateLink().waitUntilPageIsLoaded();
 ViewPage templatePage = classSheetPage.clickTemplateLink();
 assertEquals(className + " Template", templatePage.getDocumentTitle());
 // The default edit button should take us to the In-line edit mode.
 templatePage.edit();
 InlinePage editPage = new InlinePage();
 editPage.setValue("color", "red");
 editPage.setValue("age", "13");
 editPage.clickSaveAndContinue();
 editPage.clickBreadcrumbLink(classTitle);
 classSheetPage.waitUntilPageIsLoaded();

// Create a document based on the class template.
 assertEquals(spaceName, classSheetPage.getNewPagePicker().getParentInput().getAttribute("value"));
 editPage = classSheetPage.createNewDocument(spaceName, pageName);

assertEquals(pageName, editPage.getDocumentTitle());
 assertEquals("red", editPage.getValue("color"));
 assertEquals("13", editPage.getValue("age"));

editPage.setValue("color", "blue");
 editPage.setValue("age", "27");
 ViewPage viewPage = editPage.clickSaveAndView();

assertEquals(pageName, viewPage.getDocumentTitle());
 assertEquals("YOUR FAVORITE COLOR\nblue\nYOUR CURRENT AGE\n27", viewPage.getContent());
 viewPage.clickBreadcrumbLink(classTitle);
 classSheetPage.waitUntilPageIsLoaded();

maybe you could check that?
Ilie Andriuta: yes, looking now
Vincent Massol: it's about templates
not about template providers
(I think)
I don't know the feature about template provider (from the class sheet) personally
actually it vaguely rings a bell
do you know the jira issue that introduced it?
Ilie Andriuta: it was introduced in 11.8 RC1
searching for JIRA
https://jira.xwiki.org/browse/XWIKI-16725
found it
Vincent Massol: https://jira.xwiki.org/browse/XWIKI-16725
yep

seems that Alex (not on this chat, weird) might have forgotten to test it (I mean to write a test for it)
Ilie Andriuta: yes, doesn't seem that https://github.com/xwiki/xwiki-platform/blob/a6bd6aa1e3c3aa96d480812fa9f635ca369384b8/xwiki-platform-core/xwiki-platform-xclass/xwiki-platform-xclass-test/xwiki-platform-xclass-test-docker/src/test/it/org/xwiki/xclass/test/ui/ClassSheetIT.java#L45 contains the test for Provider
*Vincent Masso*l: the 3 commits don't have any test in them ....
not great
Ilie Andriuta: I'll let you create the issue and we'll link it to XWIKI-16725
it's really hard afterwards when committers don't take the time to write tests
Ilie Andriuta: ok, I'll create it
thanks